This story includes an interview with Structur3D Printing cofounder and R&D director Andrew Finkle.

Most 3-D printers are great at turning designs into solid structures, but can only build with one or two types of solid plastic. But a new Kickstarter campaign from Ontario-based Structur3D Printing offers an aftermarket add-on letting common printers work with a wide variety of gel materials to produce everything from silicone-based orthotic shoe inserts to custom cake toppers printed from icing sugar.

The Structur3D team decided early on not to try to jump into the crowded 3-D printer market by producing their own complete unit and to focus instead on expanding the capabilities of existing hardware, says cofounder and R&D director Andrew Finkle.

"One of the first things that we decided, because we are materials engineers, [is that] we wanted to focus on just the system that deposited the material," says Finkle, who's completing a PhD at the University of Waterloo. "Because they all run on very similar electronics, we were able to design an add-on."

That add-on, called the Discov3ry extruder, can be swapped in for the plastic-filament extruders included with printers from companies like MakerBot and Leapfrog. The extruder allows the printers to print with a range of gel-like materials, from meringue to hardware store silicone, loaded in refillable syringes.

"We can print things like silicone and latex and polyurethane that are extremely flexible," says Finkle, explaining those materials can be cheaper than traditional 3-D printing plastic and usable where a more rigid material isn’t.

"Imagine sliding a hard plastic orthotic into your shoe," says Finkle, explaining that orthotic makers have previously had to build or print custom rigid molds, then use them to cast the actual shoe inserts from a more suitable material.

And working with edible materials can make experimenting with 3-D printing more fun for kids, says Finkle.

"They can eat their mistakes and have a lot more fun doing it over traditional plastic printing," he says. The company plans to work with an Ontario youth maker group to experiment with printing food and other fun materials like Play-Doh, he says.

Structur3D recently had success printing 3-D images out of Nutella—one of the rewards offered to Kickstarter backers is a custom photo printed from the hazelnut spread onto a graham cracker—and the company found bakers at a local cupcake shop were excited by the printer's confectionary applications, Finkle says.

"You could also print very custom cake toppers for your child's birthday cake or a special company occasion," he says.

Once the first units ship to backers in the fall and winter, Structur3D plans to set up an area on its website where company engineers and customers can swap material ideas and tips.

"We’re going to have a very open forum," Finkle says.

The Kickstarter campaign helps to stir up consumer interest while raising money to manufacture the first set of extruders, Finkle says. At the same time, the company plans to talk to potential industrial users about potential manufacturing applications, such as for custom health products, he says. And, they hope to tweak some commonly used gel materials to make them work better with the Discov3ry system.

"Using our materials background we can tune some of these materials to make them better for 3-D printing," says Finkle.